Compact line scan mems time of flight system with actuated lens

ABSTRACT

An optical module includes an optical detector, laser emitter, and first and second support structures, each carried by a substrate. An optical layer includes first and second fixed portions carried by the support structures, a movable portion affixed between the fixed portions by a spring structure, and a lens system carried by the movable portion, the lens system including an objective lens and a beam shaping lens. The optical layer includes a comb drive with a first comb structure extending from the first fixed portion to interdigitate with a second comb structure extending from the movable portion, a third comb structure extending from the second fixed portion to interdigitate with a fourth comb structure extending from the movable portion, and actuation circuitry applying voltages to the comb structures to cause the movable portion of the optical layer to oscillate back and forth between the fixed portions.

TECHNICAL FIELD

This disclosure is related to the field of time of flight imagingsystems and, in particular, to a compact time of flight system utilizingMEMS technology to scan a transmit lens and a receive lens across apulsed laser generator and a high speed photodetector to enable depthmeasurement of a scene.

BACKGROUND

Time-of-flight (TOF) imaging techniques are used in many depth mappingsystems (also referred to as 3D mapping or 3D imaging). In so-called“direct” TOF techniques, a light source, such as a pulsed laser, directspulses of optical radiation toward the scene that is to be mapped, and ahigh-speed detector senses the time of arrival of the optical radiationreflected back from the scene. The depth value at each pixel in thedepth map is derived from the difference between the emission time ofthe outgoing pulse of optical radiation and the arrival time of theoptical radiation reflected from the corresponding point in the scene,which is referred to as the “time of flight” of the optical pulses.

For some desired applications, in order to meet desired performance andresolution metrics, it is desired to scan the optical light sourceacross the scene, and to properly receive the optical radiationreflected back from the scene during that scan. As an example, the lightsource and high-speed detector may be scanned with respect to opticallenses through which the outgoing pulses of optical radiation andincoming optical radiation reflected back from the scene.

However, current scanning techniques may consume an undesired amount ofarea. In addition, the thickness of optical modules used with suchtechniques is greater than desired Given that depth mapping systems aretypically incorporated into compact electronic devices, the excess areaconsumption and excess thickness is particularly undesirable. As such,developed into compact TOF systems utilizing a scanning solution todepth map a scene is necessary.

SUMMARY

Disclosed herein is an optical module, including: a substrate; anoptical detector carried by the substrate; a laser emitter carried bythe substrate; a support structure carried by the substrate; and anoptical layer. The optical layer includes: a fixed portion carried bythe support structure; a movable portion affixed between opposite sidesof the fixed portion by a spring structure; a lens system carried by themovable portion, the lens system including an objective lens portion anda beam shaping lens portion, the objective lens portion being positionedsuch that it overlies the optical detector, the beam shaping lensportion being positioned such that it overlies the laser emitter; and aMEMS actuator for in-plane movement of the movable portion with respectto the fixed portion.

The MEMS actuator may include a comb drive. The comb drive may be formedby: a first comb structure extending from the fixed portion tointerdigitate with a second comb structure extending from the movableportion; and actuation circuitry configured to apply voltages to thefirst and second comb structures to cause the movable portion of theoptical layer to oscillate back and forth between opposite sides of thefixed portion such that at a first travel limit the movable portion ofthe optical layer is closer to the a first side of the fixed portionthan to a second side of the fixed portion, and such that at a secondtravel limit the movable portion of the optical layer is closer to thesecond side of the fixed portion than to the first side of the fixedportion.

The MEMS actuator may be formed by: a first comb structure extendingfrom a first side of the fixed portion to interdigitate with a secondcomb structure extending from an adjacent side of the movable portion; athird comb structure extending from a second side of the fixed portionto interdigitate with a fourth comb structure extending from an adjacentside of the movable portion; and actuation circuitry configured to applyvoltages to the first, second, third, and fourth comb structures tocause the movable portion of the optical layer to oscillate back andforth between opposite sides of the fixed portion such that at a firsttravel limit the movable portion of the optical layer is closer to afirst side of the fixed portion than to a second side of the fixedportion, and such that at a second travel limit the movable portion ofthe optical layer is closer to the second side of the fixed portion thanto the first side of the fixed portion.

The optical detector may be a two dimensional array of single photonavalanche diodes arranged to match an expected diffraction patterndisplayed by light incident thereon.

The laser emitter may be a one dimensional array of vertical cavitysurface emitting lasers (VCSELs).

The spring structure may be a MEMS spring structure.

The fixed portion, movable portion, and spring structure may beintegrally formed as a monolithic unit.

An encapsulating layer may be carried by the fixed portion and overlyingthe lens system.

The lens system may include a metasurface optic.

The lens system may include an objective lens and a beam shaping lensspaced apart from the objective lens.

The lens system may be carried by a top surface of the movable portion,and a back surface of the movable portion may be thinned oppositeportions of the movable portion where the objective lens portion andbeam shaping lens portion reside.

The movable portion may include a shuttle carrying the lens system, withthe spring structure comprising first, second, third, and fourthflexures respective extending from different corners of the shuttle toanchor at different corners of the fixed portion.

The first, second, third, and fourth flexures may be S-shaped.

The shuttle may include a first shuttle portion carrying the objectivelens portion, a second shuttle portion carrying the beam shaping lensportion, and a connector portion extending between the first and secondshuttle portions, with a width of the connector portion being less thana width of the first and second shuttle portions.

The shuttle may have first and second openings defined therein in whichthe objective lens portion and the beam shaping lens portion are carried

The shuttle may be formed by first and second spaced apart shuttleportions.

The lens system may include a glass substrate carried by the movingportion, with the objective lens portion and the beam shaping lensportion being carried by the glass substrate.

An additional glass substrate may be carried by the support structure,the additional glass substrate carrying the optical layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of an embodiment of amicroelectromechanical system (MEMS) based optical module for a time offlight (TOF) system.

FIG. 1A is a top view of the MEMS based optical module of FIG. 1.

FIG. 2 is a top view of the reflected optical radiation incident on theoptical detector of FIG. 1, after it has passed through a diffractiveoptic.

FIG. 3 is a top view of the laser emitters forming the light source ofFIG. 1.

FIG. 4 is a top view of a first possible arrangement for the layercontaining the MEMS actuators and optic carrying shuttle of FIG. 1.

FIG. 5 is a top view of a second possible arrangement for the layercontaining the MEMS actuators and optic carrying shuttle of FIG. 1.

FIG. 6 is a top view of a third possible arrangement for the layercontaining the MEMS actuators and optic carrying shuttle of FIG. 1.

FIG. 7 is a cross sectional view of an additional embodiment of a MEMSbased optical unit for a TOF system, such as may use the arrangements ofFIGS. 4-6 for its layer containing the MEMS actuators and optic carryingshuttle.

FIG. 8 is a cross sectional view of an another embodiment of a MEMSbased optical unit for a TOF system, such as may use the arrangements ofFIGS. 4-6 for its layer containing the MEMS actuators and optic carryingshuttle.

FIG. 9 is a cross sectional view of a further embodiment of a MEMS basedoptical unit for a TOF system, such as may use the arrangements of FIGS.4-6 for its layer containing the MEMS actuators and optic carryingshuttle.

FIG. 10 is a cross sectional view of the embodiment of the MEMS basedoptical unit of FIG. 7, encapsulated by a glass layer.

FIG. 11 is a top view of the MEMS based optical unit of FIG. 10.

FIG. 12 is a cross sectional view of yet another embodiment of a MEMSbased optical unit for a TOF system, such as may use the arrangements ofFIGS. 4-6 for its layer containing the MEMS actuators and optic carryingshuttle.

FIG. 13 is a cross sectional view of a variant of the embodiment of FIG.12, where the optic layer and MEMS layer are encapsulated by glasssubstrates.

FIG. 14 is a cross sectional view of a variant of the embodiment of FIG.1, where the lens overlying the laser emitter array is moved by theshuttle while the lens overlying the optical sensor remains stationary.

FIG. 15 is a cross sectional of another variant of the embodiment ofFIG. 1, where the lens overlying the laser emitter array is moved by theshuttle while the lens overlying the optical sensor is a conventionallyformed lens and remains stationary.

DETAILED DESCRIPTION

The following disclosure enables a person skilled in the art to make anduse the subject matter disclosed herein. The general principlesdescribed herein may be applied to embodiments and applications otherthan those detailed above without departing from the spirit and scope ofthis disclosure. This disclosure is not intended to be limited to theembodiments shown, but is to be accorded the widest scope consistentwith the principles and features disclosed or suggested herein.

Now described with reference to FIG. 1 is a MEMS based optical module 10for use in a TOF system. The optical module 10 includes a substrate 11,such as silicon or an organic material, on which a high speed opticaldetector integrated circuit (IC) 13 and a laser emitter array integratedcircuit (IC) 14 are mounted. As an example, the MEMS based opticalmodule 10 may be realized using an assembly process in which the highspeed optical detector IC 13 and laser emitter array IC 14 are mountedby die attach to the substrate 11, utilizing back-end processingtechniques.

The high speed optical detector IC 13 may be comprised of atwo-dimensional array of single photon avalanche diodes (SPADs), and thelaser emitter array IC 14 may be comprised of an array (one dimensionalor two dimensional) of vertical cavity surface emitting lasers (VCSELs).Support structures 12 a and 12 b are carried by the substrate 11 onopposite sides of the optical detector IC 13 and laser emitter array IC14, and may also be formed from silicon, metal, or plastics. The supportstructures 12 a and 12 b may be opposite sides of a frame shaped supportstructure 12, as shown in FIG. 1A

An optic layer 19 is carried by the support structures 12 a and 12 b.The optic layer 19 is comprised of fixed portions 15 a and 15 b carriedby the respective support structures 12 a and 12 b. The fixed portions15 a and 15 b may be formed from silicon. The fixed portions 15 a and 15b may be opposite sides of a frame shaped fixed portion 15, as shown inFIG. 1A.

Between the fixed portions 15 a and 15 b is a moving portion 16, whichmay also be formed by silicon or by an optically transparent material.Although not shown in FIG. 1, as will be explained below, MEMS flexuresextend from the moving portion 16 to anchor points on the fixed portions15 a and 15 b, and when the moving portion 16 is actuated, serve topermit movement of the moving portion 16 in the positive and negativex-direction (away from one fixed portion 15 a and toward the other fixedportion 15 b, then away from the fixed portion 15 b and back toward thefixed portion 15 a, and so on). Lenses 17 a and 17 b are carried by themoving portion 16, with lens 17 a being positioned on the moving portion16 so that it overlies the optical detector IC 13, and lens 17 b beingpositioned on the moving portion 16 so that it overlies the laseremitter array IC 14. Note that lens 17 a is sized such that, regardlessof the position of the moving portion 16 as it moves, light 9 incidenton the lens 17 a is bent by the lens 17 a such that it impinges upon theoptical detector IC 13, and such that light 18 emitted by the laseremitter IC array IC 14 is bent by the lens 17 b such that it is directedat a desired angle toward the scene (for example, in the z-direction).

Lens 17 a is an objective lens and focuses the light reflected from thescene to the optical detector IC 13, and may be a multi-leveldiffractive optic or a metasurface. The light reflected from the scenehas a pattern of parallel lines, due to the pattern of the lasers of thelaser emitter array IC 14, explained below. The incident light reflectedfrom the scene at which it was directed by the laser emitter array IC 14and lens 17 b may be seen in FIG. 2, where it can observed that theincident light 19 has been focused into the pattern of parallel lines onthe optical detector IC 13 shown in FIG. 2. Note that in some cases, theSPADs of the optical detector IC 13 may be pre-arranged into thispattern at the time of the formation of the optical detector IC 13.

Lens 17 b is a beam shaping optic and is shaped and formed so as tocollimate the laser light 18 emitted by the VCSELs of the laser emitterarray IC 14 along a direction parallel to the MEMS scan direction, andto expand the circular beam of each laser shown in FIG. 3 along adirection perpendicular to this direction. As a result, as shown in FIG.2, a light pattern comprised of a set of parallel lines is obtained.This pattern is scanned along the MEMS scanning direction by themovement of the moving portion 16. The lens 17 b may also be amulti-level diffractive optic or a metasurface. Note that the laseremitter array IC 14 may be a one dimensional array or line of VCSELs.

A top view of one potential arrangement for the optic layer 19 may beseen in FIG. 4. The moving portion 16 includes a shuttle 20, with thelenses 17 a and 17 b affixed within openings in the shuttle 20. Flexures22 a-22 d formed using MEMS technology extend in a squared off S-patternfrom the corners of the shuttle 20 to anchor points 23 a-23 d that areaffixed to the fixed portions 15 a and 15 b, with anchor point 23 a and23 d being affixed to fixed portion 15 a, and anchor points 23 b and 23c being affixed to fixed portion 15 b. Note that the flexures 22 a-22 dare actually integrally formed with the shuttle 20 and fixed portions 15a and 15 b as a monolithic unit, and therefore extend from the shuttle20 to the fixed portions 15 a and 15 b instead of being affixed to theshuttle 20 and fixed portions 15 a and 15 b.

Conductive combs 25 a and 25 b extend from the sides of the shuttle 20,and are interdigitated with conductive combs 26 a and 26 b that extendfrom comb drive actuators 24 a and 24 b that are respectively affixed tothe fixed portions 15 a and 15 b. The combs 25 a and 25 b are integrallyformed with the shuttle 20 and flexures 22 a-22 d as a monolithic unit,and therefore they are short circuited together and set at a constantreference voltage (e.g., ground) by biasing the fixed portions 15 a and15 b at which they are connected. The electrical routing is realizedthrough the flexures 22 a-22 d themselves. The comb drive actuators 24 aand 24 b are circuits configured to apply a voltage (a DC bias with asuperimposed AC drive waveform) to the combs 26 a and 26 b so that acomb drive is formed, and the shuttle 20 is moved back and forth in thex-direction via electrostatic actuation to thereby scan the laser pulsesemitted by the laser emitter array IC 14 across the scene to permitdetection of reflections therefrom by the optical detector IC 13 tocollecting depth information about the scene. Note that since the lenses17 a and 17 b are on the same shuttle 20, both the light emitted by thelaser emitter array IC 14 and the light collected at the opticaldetector 13 is scanned synchronously, so that the optical detector 13views the portion of the scene illuminated by the laser emitter array IC14 at any given movement and in such a way that less background lightthan reflected laser light is collected, since the optical detector 13is viewing but a portion of the scene at a given time.

In the above examples, the thickness tsi of the substrate 11 may be onthe order of 200 μm to 300 μm. The thickness of the layers 15 and 16 maybe on the order of 60 μm. In addition, the length Lx of the lenses 17 aand 17 b may be 3.25 mm, and the width Ly of the lenses 17 a and 17 bmay be 2.5 mm.

A variant of the optical layer 19′ is seen in FIG. 5. Here, the shuttleis divided into a first shuttle portion 20 a carrying the lens 17 a, anda second shuttle portion 20 b carrying the lens 17 b, with a connectorportion 33 extending between the first shuttle portion 20 a and secondshuttle portion 20 b. Note that the connector portion 33 is narrower inthe z-direction than the first shuttle portion 20 a and second shuttleportion 20 b, and is integrally formed with the first and second shuttleportions as a monolithic unit. Note here that in addition to theflexures 22 a-22 d extending from the outside corners of the firstshuttle portion 20 a and seconds shuttle portion 25 b, flexures 29 a and31 a extend from the inside corners of the first shuttle portion 20 a,while flexures 29 b and 31 b extend from the inside corners of thesecond shuttle portion 20 b. Each flexure 22 a-22 d, 29 a-29 b, and 31a-31 b is U-shaped, and extends toward respective anchor points 23 a-23d, 30 a-30 b, and 32 a-32 b. Flexures 22 a, 22 d, 29 a, 31 a areintegrally formed with shuttle portion 20 a as a monolithic unit, andflexures 22 b, 22 c, 29 b, 31 b are integrally formed with shuttleportion 20 b as a monolithic unit. Operation of the optical layer 19′ isthe same as the optical layer 19 described above.

Another variant of the optical layer 19″ is seen in FIG. 6. Here, it canbe observed that, as compared to the optical layer 10′ of FIG. 5, thereis no connector portion 33, and that shuttle portions 20 a′ and 20 b′are separate unconnected components. Keeping in mind that the fixedportion 15 may be shaped as a frame (FIG. 1A), the anchor points 30 aand 30 b, and 32 a and 32 b are connected to and supported by the fixedportion 15. Note here that while the lenses 17 a and 17 b are scannedsynchronously, this is not accomplished passively by being carried bythe same shuttle, but is instead accomplished by the driving of the combdrive being such that the first shuttle portion 20 a′ and second shuttleportion 20 b′ move synchronously.

In a situation where it would be desired for the shuttle 20 to beopaque, as shown in FIG. 7, the moving portion may be separated into twodisconnected and spaced apart moving portions 16 a and 16 b bycompletely removing portions of the fixed portion from the side thereofopposite the lenses 17 (here, the lenses 17 a and 17 b are formed as onemetalens with a diffractive portion 17 a and a collimating portion 17b), such as by using silicon deep reactive ion etching. As analternative, windows may be formed within the moving portion 16, and thelenses 17 a and 17 b are held within those windows.

As an alternative as shown in FIG. 8, a thin layer (e.g., 1-5 micronsthick) of the moving portion 16 may be left adjacent the diffractiveportion 17 a and collimating portion 17 b if the moving portion 16 isformed from silicon.

As another alternative shown in FIG. 9, moving portion 16 is separatedinto two spaced apart moving portions 16 a and 16 b, with a glasssubstrate 36 extending on top of and between the moving portions 16 aand 16 b, and the lens 17 being carried by the glass substrate 36.

In any arrangement described herein, the moving portion 16 may havefirst and second openings defined therein for carrying the lenses 17 aand 17 b.

Note that any of the variants of the optical layer described above maybe encapsulated by a glass layer 44 carried by support blocks 43 a and43 b which are in turn carried by the spaced apart fixed portions 15 aand 15 b, as shown in FIG. 10. A top view of this embodiment may befound in FIG. 11, where it can be observed that the support structures12 a and 12 b may be opposite sides of a frame shaped support structure12, the fixed portions 15 a and 15 b may be opposite sides of a frameshaped fixed portion 15, and the support blocks 43 a and 43 b may beopposite sides of a frame shaped support block 43.

A variant of the design of FIG. 10 is shown in FIG. 12, where the fixedportions 15 a and 15 b are carried by support portions 51 a and 51 b(that also may be opposite sides of a frame shaped support portion), andthat electrical routing 52 may extend through the support portion 51 abetween the fixed portion 15 a and a terminal carrying block 53, with ametal pad 54 for wire bonding being carried by the terminal carryingblock 53 and electrically coupled to the electrical routing 52.

A further embodiment is shown in FIG. 13, where, instead of the glasssubstrate 44 encapsulating the lens 17, optical detector 13, and laseremitter array 14 against the substrate 11, the support portions 51 a and51 b are carried by a second glass substrate 55, which is in turncarried by the support structures 12 a and 12 b extending from thesubstrate 11. Therefore, in this embodiment, the lens 17, fixed portions15 a and 15 b, and moving portions 16 a and 16 b are encapsulated byglass on both sides, providing enhanced environmental protection. Thisembodiment also allows for low pressure operation, increasingefficiency. Also note here that this structure may be used inapplications unrelated to depth sensing, such as picoprojection. In sucha case, the optical detector 13 is removed, and the size of the othercomponents adjusted accordingly.

Returning now to the general design of FIG. 1, a variant is shown inFIG. 14. Here, the lens 17 a is still contained within the optic layer19, but is attached to and carried by the fixed portion 15 a. Therefore,here, the lens 17 a is not moved, while the lens 17 b is still moved asdescribed above.

As a further alternative shown in FIG. 15, rather than a lens 17 a beingwithin the optic layer 19 a, the fixed portion 15 a is frame shaped andseparated from the fixed portion 15 b, and contains a standard imaginglens 17 c. Therefore, here, the lens 17 c is now moved, while the lens17 b is still moved as described above. Here, a bonding pad 99 iscarried by the fixed portion 15 a, and used for applying a drive signalto the MEMS actuator.

In the above examples, the moving portion 16 is moved by a comb drive,but it should be understood that any MEMS actuation technique may beused. For example, thermal, magnetic, and piezoelectric actuation may beused to move the moving portion 16 with respect to the fixed portion 15,

While the disclosure has been described with respect to a limited numberof embodiments, those skilled in the art, having benefit of thisdisclosure, will appreciate that other embodiments can be envisionedthat do not depart from the scope of the disclosure as disclosed herein.Accordingly, the scope of the disclosure shall be limited only by theattached claims.

1. An optical module, comprising: a substrate; an optical detectorcarried by the substrate; a laser emitter carried by the substrate; asupport structure carried by the substrate; an optical layer comprising:a fixed portion carried by the support structure; a movable portionaffixed between opposite sides of the fixed portion by a springstructure; a lens system carried by the movable portion, the lens systemincluding an objective lens portion and a beam shaping lens portion, theobjective lens portion being positioned such that it overlies theoptical detector, the beam shaping lens portion being positioned suchthat it overlies the laser emitter; and a MEMS actuator for in-planemovement of the movable portion with respect to the fixed portion. 2.The optical module of claim 1, wherein the MEMS actuator comprises: acomb drive comprising: a first comb structure extending from the fixedportion to interdigitate with a second comb structure extending from themovable portion; actuation circuitry configured to apply voltages to thefirst and second comb structures to cause the movable portion of theoptical layer to oscillate back and forth between opposite sides of thefixed portion such that at a first travel limit the movable portion ofthe optical layer is closer to the a first side of the fixed portionthan to a second side of the fixed portion, and such that at a secondtravel limit the movable portion of the optical layer is closer to thesecond side of the fixed portion than to the first side of the fixedportion.
 3. The optical module of claim 1, wherein the MEMS actuatorcomprises: a first comb structure extending from a first side of thefixed portion to interdigitate with a second comb structure extendingfrom an adjacent side of the movable portion; a third comb structureextending from a second side of the fixed portion to interdigitate witha fourth comb structure extending from an adjacent side of the movableportion; and actuation circuitry configured to apply voltages to thefirst, second, third, and fourth comb structures to cause the movableportion of the optical layer to oscillate back and forth betweenopposite sides of the fixed portion such that at a first travel limitthe movable portion of the optical layer is closer to a first side ofthe fixed portion than to a second side of the fixed portion, and suchthat at a second travel limit the movable portion of the optical layeris closer to the second side of the fixed portion than to the first sideof the fixed portion.
 4. The optical module of claim 1, wherein theoptical detector comprises a two dimensional array of single photonavalanche diodes arranged to match an expected diffraction patterndisplayed by light incident thereon.
 5. The optical module of claim 1,wherein the laser emitter comprises a one dimensional array of verticalcavity surface emitting lasers (VCSELs).
 6. The optical module of claim1, wherein the spring structure is a MEMS spring structure.
 7. Theoptical module of claim 1, wherein the first portion, movable portion,and spring structure are integrally formed as a monolithic unit.
 8. Theoptical module of claim 1, further comprising an encapsulating layercarried by the fixed portion and overlying the lens system.
 9. Theoptical module of claim 1, wherein the lens system comprises ametasurface optic.
 10. The optical module of claim 1, wherein the lenssystem is comprised of an objective lens and a beam shaping lens spacedapart from the objective lens.
 11. The optical module of claim 1,wherein the lens system is carried by a top surface of the movableportion; and wherein a back surface of the movable portion is thinnedopposite portions of the movable portion where the objective lensportion and beam shaping lens portion reside.
 12. The optical module ofclaim 1, wherein the movable portion is comprised of a shuttle carryingthe lens system, with the spring structure comprising first, second,third, and fourth flexures respective extending from different cornersof the shuttle to anchor at different corners of the fixed portion. 13.The optical module of claim 12, wherein the first, second, third, andfourth flexures are S-shaped.
 14. The optical module of claim 12,wherein the shuttle is comprised of a first shuttle portion carrying theobjective lens portion, a second shuttle portion carrying the beamshaping lens portion, and a connector portion extending between thefirst and second shuttle portions, a width of the connector portionbeing less than a width of the first and second shuttle portions. 15.The optical module of claim 12, wherein the shuttle has first and secondopenings defined therein in which the objective lens portion and thebeam shaping lens portion are carried
 16. The optical module of claim12, wherein the shuttle is comprised of first and second spaced apartshuttle portions.
 17. The optical module of claim 1, wherein the lenssystem includes a glass substrate carried by the moving portion, withthe objective lens portion and the beam shaping lens portion beingcarried by the glass substrate.
 18. The optical module of claim 1,further comprising an additional glass substrate carried by the supportstructure, the additional glass substrate carrying the optical layer.19. An optical module, comprising: a substrate; an optical circuitcarried by the substrate; an optical layer comprising: a fixed portioncarried by the substrate; a moving portion affixed between oppositesides of the fixed portion by a spring structure; a lens system carriedby the moving portion, the lens system being aligned with the opticalcircuit; a comb drive formed by respective features of the fixed portionand moving portion; and actuation circuitry configured to apply a drivesignal to the comb drive to thereby cause electrostatic actuation to thecomb drive resulting in the moving portion of the optical layeroscillating back and forth between opposite sides of the fixed portion.20. The optical module of claim 19, wherein the optical circuit includesan optical detector comprising a two dimensional array of single photonavalanche diodes arranged to match an expected diffraction patterndisplayed by light incident thereon.
 21. The optical module of claim 19,wherein the optical circuit includes an array of vertical cavity surfaceemitting lasers (VCSELs).
 22. The optical module of claim 19, whereinthe spring structure is a MEMS spring structure.
 23. The optical moduleof claim 19, wherein the fixed portion, movable portion, and springstructure are integrally formed as a monolithic unit.
 24. The opticalmodule of claim 19, further comprising an encapsulating layer carried bythe moving portion and overlying the lens system.
 25. The optical moduleof claim 19, wherein the lens system comprises a metasurface optic. 26.The optical module of claim 19, wherein the lens system is comprised ofan objective lens and a beam shaping lens spaced apart from theobjective lens.
 27. The optical module of claim 19, wherein the lenssystem is carried by a top surface of the moving portion; and wherein aback surface of the moving portion is thinned opposite portions of themoving portion.
 28. The optical module of claim 19, wherein the movingportion is comprised of a shuttle carrying the lens system, with thespring structure comprising first, second, third, and fourth flexuresrespective extending from different corners of the shuttle to anchor atdifferent corners of the fixed portion.
 29. The optical module of claim28, wherein the shuttle is comprised of a first shuttle portion carryingan objective lens portion, a second shuttle portion carrying a beamshaping lens portion, and a connector portion extending between thefirst and second shuttle portions, a width of the connector portionbeing less than a width of the first and second shuttle portions. 30.The optical module of claim 28, wherein the shuttle is comprised offirst and second spaced apart shuttle portions.
 31. The optical moduleof claim 19, wherein the lens system includes a glass substrate carriedby the moving portion, with a first lens portion and a second lensportion being carried by the glass substrate.
 32. The optical module ofclaim 31, further comprising an additional glass substrate carried by asupporting structure extending from the substrate, the additional glasssubstrate carrying the optical layer.
 33. An optical module, comprising:a substrate; an optical detector carried by the substrate; a laseremitter carried by the substrate; a support structure carried by thesubstrate; an optical layer comprising: a fixed portion carried by thesupport structure; a movable portion affixed between opposite sides ofthe fixed portion by a spring structure; a first lens system carried bythe movable portion and overlying the laser emitter; and a MEMS actuatorfor in-plane movement of the movable portion with respect to the fixedportion.
 34. The optical module of claim 33, wherein the optical layerincludes a second lens system carried by the fixed portion and overlyingthe optical detector.
 35. The optical module of claim 34, wherein thefirst and second lens systems are MEMS lens systems.
 36. The opticalmodule of claim 34, wherein the first lens system is a MEMS lens system,and the second lens system is a non-MEMS lens system.